Study guide
7.3 Complex Regional Pain Syndrome, Fibromyalgia & Myofascial Pain
ABPMR Physical Medicine and Rehabilitation Board Exam Study Guide Exam
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1 Chapter 1: Introduction & Exam Overview
1.1 ABPMR Part I Exam Overview & Format 1.2 Board Review Strategy & Content Blueprint Breakdown
2 Chapter 2: Musculoskeletal Medicine
2.1 Shoulder & Upper Extremity Diagnostics 2.2 Knee, Hip & Lower Extremity Conditions 2.3 Spine Pathology, Radiculopathy & Myelopathy 2.4 Inflammatory Arthritis, Tendinopathies & Concussion 2.5 Bone Health, Osteoporosis & Metabolic Bone Disease 2.6 Thoracic Outlet Syndrome & Peripheral Nerve Entrapment 2.7 Fracture Rehabilitation & Immobilization Complications 2.8 Overuse Tendinopathies & Regenerative Medicine 2.9 Gait Analysis & Abnormal Gait Patterns
3 Chapter 3: Spinal Cord Injury Rehabilitation
3.1 ASIA Examination & Impairment Scale 3.2 Spinal Cord Injury Syndromes 3.3 Autonomic Dysreflexia & Acute Complications 3.4 Neurogenic Bladder, Bowel & Secondary Complications
4 Chapter 4: Stroke & Neuromuscular Rehabilitation
4.1 Stroke Vascular Syndromes & Acute Assessment 4.2 Stroke Motor Recovery & Hemiplegic Complications 4.3 Spasticity Assessment & Multimodal Management 4.4 ALS, GBS, CIDP & Neuromuscular Disease Rehab 4.5 Multiple Sclerosis & Demyelinating Disease Rehabilitation 4.6 Parkinsonism, Movement Disorders & Functional Neurologic Disorder
5 Chapter 5: Electrodiagnostics (EMG/NCS)
5.1 Nerve Conduction Studies Principles & Physics 5.2 Needle Electromyography & MUAP Analysis 5.3 Mononeuropathies & Radiculopathy Patterns 5.4 Neuromuscular Junction Disorders & Myopathies
6 Chapter 6: Traumatic Brain Injury
6.1 TBI Severity Classification, Glasgow Coma Scale, and Pathophysiology 6.2 Rancho Los Amigos Levels of Cognitive Functioning and Disability Rating Scale 6.3 Neurobehavioral Sequelae and Agitation Management 6.4 Concussion Evaluation, Vestibular-Ocular Dysfunction, and Return-to-Play/Work Protocols
7 Chapter 7: Chronic Pain & Interventional Spine
7.1 Fluoroscopic Spine Interventions 7.2 Opioid Stewardship & Controlled Substance Compliance 7.3 Complex Regional Pain Syndrome, Fibromyalgia & Myofascial Pain 7.4 Spinal Cord Stimulation & Intrathecal Therapy
8 Chapter 8: Amputee Rehabilitation & Prosthetics
8.1 Amputation Surgical Levels & Medicare K-Levels 8.2 Socket Designs & Suspension Systems 8.3 Prosthetic Feet & Microprocessor Knee Mechanisms 8.4 Post-Amputation Care, Residual Limb & Phantom Pain
9 Chapter 9: Pediatric Rehabilitation
9.1 Cerebral Palsy Classification & GMFCS 9.2 Spina Bifida & Myelomeningocele Management 9.3 Muscular Dystrophies & Neuromuscular Disease in Children 9.4 Pediatric Brachial Plexopathy & Congenital Disorders
10 Chapter 10: Prosthetics, Orthotics & Assistive Technology
10.1 Lower Limb Orthoses — AFOs & KAFOs 10.2 Spinal & Upper Extremity Orthoses 10.3 Upper Limb Prosthetics — Body-Powered vs Myoelectric 10.4 Wheelchairs, Seating Systems & Pressure Mapping
11 Chapter 11: Medical Rehabilitation & Outcomes
11.1 Dysphagia Assessment & Management 11.2 Neurogenic Bladder & Bowel Management 11.3 Pressure Injuries & Wound Management 11.4 Outcome Measures & Medical Complications 11.5 Cancer Rehabilitation & Oncologic Rehabilitation 11.6 Burns, Endocrine/Metabolic & Medical Complications Rehabilitation
12 Chapter 12: Cardiopulmonary Rehabilitation
12.1 Cardiac Rehabilitation Phases & Metabolic Equivalents 12.2 Pulmonary Rehabilitation & COPD Management
13 Chapter 13: Foundational Rehabilitation Concepts
13.1 Kinesiology, Biomechanics & Functional Anatomy 13.2 Rehabilitation Pharmacology & Medication Management 13.3 Research Methodology, Biostatistics & Evidence-Based Practice 13.4 Nutrition, Metabolism & Energy Expenditure in Rehabilitation 13.5 Diagnostic Procedures: Imaging, MSK Ultrasound, Urodynamics & Neuropsych Assessment
7.3 Complex Regional Pain Syndrome, Fibromyalgia & Myofascial Pain
Key Takeaways Explain This Topic AI
Complex Regional Pain Syndrome (CRPS) Type I lacks demonstrable nerve injury, whereas CRPS Type II presents with a defined major nerve lesion; diagnosis requires meeting the clinical Budapest criteria.
Triple-phase bone scan showing diffuse pericapsular hypermetabolism in Phase 3 supports early CRPS diagnosis.
Fibromyalgia is a central sensitization disorder diagnosed using the 2016 ACR criteria (Widespread Pain Index and Symptom Severity Scale); FDA-approved first-line medications include duloxetine, milnacipran, and pregabalin.
Myofascial Pain Syndrome is characterized by hyperirritable trigger points within taut muscle bands that cause referred pain and local twitch responses upon palpation, distinguishing them from fibromyalgia tender points.
Last updated: July 2026
Complex Regional Pain Syndrome, Fibromyalgia & Myofascial Pain
Chronic pain syndromes encompass a heterogeneous group of conditions characterized by altered peripheral and central pain processing. Mastering the diagnostic criteria, physiological mechanisms, and targeted therapies for Complex Regional Pain Syndrome (CRPS), Fibromyalgia, and Myofascial Pain Syndrome (MPS) is essential for physical medicine and rehabilitation specialists.
Complex Regional Pain Syndrome (CRPS)
Complex Regional Pain Syndrome is a debilitating neuropathic pain condition that typically affects a distal limb following tissue trauma, fracture, or surgery. The pain is characteristically disproportionate in magnitude and duration to the inciting event and is accompanied by autonomic, motor, sensory, and trophic disturbances.
CRPS Type I vs CRPS Type II
CRPS Type I (formerly known as Reflex Sympathetic Dystrophy [RSD] ): Represents approximately 90% of cases. Occurs without evidence of a specific, major peripheral nerve lesion . Common precipitating events include distal radius fractures, ankle sprains, crush injuries, stroke, or prolonged limb immobilization.
CRPS Type II (formerly known as Causalgia ): Defined by the presence of a confirmed, major peripheral nerve injury (e.g., median or sciatic nerve transection/laceration).
Pathophysiology
CRPS involves a complex interplay of neurogenic inflammation (exaggerated release of substance P and calcitonin gene-related peptide [CGRP]), autonomic dysregulation (sympathetic sprouting and catecholamine hypersensitivity, leading to sympathetic-maintained pain), and central sensitization (spinal cord dorsal horn hyperexcitability and cortical reorganization).
Budapest Clinical Diagnostic Criteria
Diagnosis is made clinically using the validated Budapest Diagnostic Criteria . To meet clinical diagnostic criteria, the patient must have continuing pain disproportionate to any inciting event AND:
Must report at least one symptom in three of the four following categories:
Sensory : Hyperalgesia (increased pain response to noxious stimuli) or allodynia (pain due to normally non-noxious stimuli such as light touch or clothing).
Vasomotor : Temperature asymmetry ( > 1.0 ∘ C >1.0^\circ\text{C} > 1. 0 ∘ C ) or skin color changes/asymmetry.
Sudomotor / Edema : Edema, sweating changes, or sweating asymmetry.
Motor / Trophic : Decreased range of motion, motor dysfunction (weakness, tremor, dystonia), or trophic changes (altered hair growth, nail changes, skin atrophy).
Must display at least one sign at the time of examination in two or more of those same four categories.
No other diagnosis better explains the signs and symptoms.
Diagnostic Testing
Triple-Phase Bone Scan : Phase 1 (flow) and Phase 2 (blood pool) show increased vascular perfusion; Phase 3 (delayed 3-hour tissue phase) characteristically shows diffuse, asymmetric pericapsular hypermetabolism (increased radiotracer uptake) in the periarticular joints of the affected extremity. This finding is highly specific during the early stages of CRPS.
Radiographs : May reveal patchy, subperiosteal osteoporosis ( Sudeck atrophy ) in chronic stages.
Diagnostic Sympathetic Blocks : Stellate ganglion block (for upper extremity) or lumbar sympathetic block (for lower extremity) using local anesthetic confirms sympathetic-maintained pain if significant temporary temperature elevation and pain relief occur.
Interdisciplinary Treatment
Physical & Occupational Therapy : The primary cornerstone of treatment. Emphasizes active desensitization , gradual weight-bearing, edema control, and functional range of motion. Passive immobilization worsens outcome.
Pharmacotherapy : Short-course oral steroids (prednisone taper for acute inflammation), bisphosphonates (to inhibit osteoclast activity and bone turnover), gabapentinoids (gabapentin, pregabalin), and SNRIs.
Interventional Procedures : Sympathetic nerve blocks, spinal cord stimulation (SCS) for severe, refractory cases.
Fibromyalgia
Fibromyalgia is a non-articular chronic pain syndrome characterized by widespread musculoskeletal pain , fatigue, sleep disturbance, and cognitive dysfunction ("fibro-fog").
Pathophysiology: Central Sensitization
Fibromyalgia is fundamentally a disorder of central pain augmentation (central sensitization). Functional neuroimaging and CSF studies demonstrate elevated levels of excitatory neurotransmitters (substance P, glutamate) in the central nervous system alongside diminished activity in descending inhibitory monoaminergic (serotonergic and noradrenergic) pain pathways. This leads to generalized hyperalgesia and allodynia without peripheral tissue inflammation or tissue damage.
American College of Rheumatology (ACR) Diagnostic Criteria
The diagnostic framework evolved from the 1990 criteria (which required manual palpation of at least 11 of 18 specific "tender points") to the updated 2010/2016 ACR Criteria , which eliminate manual tender point counts in favor of quantitative self-reported indices:
Widespread Pain Index (WPI) : Assesses pain presence across 19 specified body regions (score 0-19).
Symptom Severity Scale (SSS) : Rates severity of fatigue, waking unrefreshed, and cognitive symptoms (score 0-12).
Diagnostic Threshold : WPI ≥ 7 \ge 7 ≥ 7 and SSS ≥ 5 \ge 5 ≥ 5 , OR WPI 4-6 and SSS ≥ 9 \ge 9 ≥ 9 .
Symptoms must be present at a similar level for at least 3 months .
Pain must be widespread, defined as pain in at least 4 of 5 regions (left upper, right upper, left lower, right lower, axial).
Pharmacological Management (FDA-Approved)
Three medications are currently FDA-approved for fibromyalgia:
Duloxetine (SNRI): Inhibits reuptake of serotonin and norepinephrine, enhancing descending inhibitory pain pathways. Highly effective for pain, fatigue, and comorbid depression.
Milnacipran (SNRI): Dual serotonin-norepinephrine reuptake inhibitor with greater selectivity for norepinephrine reuptake inhibition. Improves pain and fatigue.
Pregabalin (Alpha-2-delta ligand): Binds the α 2 δ \alpha_2\delta α 2 δ auxiliary subunit of presynaptic voltage-gated calcium channels in the CNS, reducing calcium influx and inhibiting release of excitatory neurotransmitters (glutamate, substance P).
Contraindication : Opioids are ineffective and contraindicated in fibromyalgia; they do not target central sensitization and can exacerbate hyperalgesia (opioid-induced hyperalgesia).
Myofascial Pain Syndrome (MPS)
Myofascial Pain Syndrome is a regional musculoskeletal pain disorder characterized by painful, localized trigger points in skeletal muscle and surrounding fascia.
Trigger Points vs Fibromyalgia Tender Points
Distinguishing trigger points from tender points is a classic board examination distinction:
Myofascial Trigger Point :
Located within a taut band of skeletal muscle.
Extremely focal tenderness; palpation produces a characteristic referred pain pattern distant from the site of pressure.
Mechanical stimulation (snapping palpation or needle insertion) elicits a local twitch response (LTR) —an involuntary contraction of muscle fibers within the taut band.
Fibromyalgia Tender Point :
Widespread tenderness without a palpable muscle taut band.
Palpation produces local tenderness only, without referred pain patterns or local twitch responses.
Treatment Strategies
Trigger Point Injections (TPI) : Infiltration of local anesthetic (e.g., 0.5% procaine or 0.25% bupivacaine) into the trigger point. The therapeutic mechanism is primarily mechanical disruption of the dysfunctional motor endplates combined with anesthetic pain relief.
Dry Needling : Insertion of an acupuncture needle into the trigger point to elicit an LTR without injectate. Equivalent in long-term efficacy to TPI with local anesthetic.
Spray-and-Stretch : Application of a vapocoolant spray (e.g., ethyl chloride) over the muscle to block cutaneous nociceptive input, followed immediately by passive stretching of the muscle to restore resting length.
Feature Complex Regional Pain Syndrome (CRPS) Fibromyalgia Myofascial Pain Syndrome (MPS)
Primary Location Distal extremity (asymmetric) Widespread (axial & 4 quadrants) Regional (specific muscle groups)
Pathophysiology Autonomic dysregulation & neurogenic inflammation Central sensitization / pain amplification Local dysfunctional motor endplates / taut bands
Diagnostic Hallmarks Budapest criteria; Triple-phase bone scan pericapsular uptake 2016 ACR criteria (WPI & SSS scores) Palpable taut band, referred pain, local twitch response
Autonomic / Trophic Signs Present (sweating, edema, skin color/temp changes) Absent Absent
First-Line Pharmacotherapy Gabapentinoids, short steroids, bisphosphonates Duloxetine, Milnacipran, Pregabalin Local NSAIDs, muscle relaxants, local anesthetics
Interventional Treatment Sympathetic blocks, SCS None (opioids contraindicated) Trigger point injections, dry needling, spray-and-stretch